Pre-Operative Nodal Staging of Thyroid Cancer Using USPIO MRI: Preliminary Study

Inclusion Criteria:

* Subjects must have either primary or recurrent PTC or MTC with nodal metastases detected through physical examination and/or standard imaging techniques.
* Subjects must be deemed eligible for resection by a surgeon who is listed as an Investigator in this study;
* Age \> 18 years;
* Subjects must be willing and able to understand and sign Informed Consent.
* No uncontrolled serious medical or psychiatric illness.
* Women of childbearing potential must not be pregnant or lactating.
* Subjects will have had standard care CT, MRI, or ultrasound, and a fine-needle aspiration biopsy demonstrating PTC or MTC with nodal metastases or recurrent/persistent nodal disease in a patient with known PTC or MTC.

Exclusion Criteria:

* Subjects who have a known allergy to iron;
* Subjects who are pregnant or lactating;
* Subjects who are less than 18 year of age;
* Subjects with a counter-indication to MRI, such as the presence of metallic prostheses or implanted metal device (e.g., infusion pump, defibrillator)
* Subjects with sickle cell disease, hemoglobinopathy, hemochromatosis or other clinical conditions that may lead to iron overload.
* State a medical or scientific reason if women who are pregnant or nursing will be excluded from the study. Guidelines and procedures pertinent to this requirement are available at: http://ctep.cancer.gov/protocolDevelopment/templates\_applications.htm. Suggested text is provided below and may be modified as necessary.

Pregnant women are excluded from this study because there are no studies of ferumoxytol in pregnant women. In animal studies, ferumoxytol caused decreased fetal weights and fetal malformations at maternally toxic doses of 13-15 times the human dose. It is unknown if ferumoxytol is present in human milk. Because of the potential for adverse events in nursing infants, a decision should be made whether to discontinue nursing or to avoid ferumoxytol.

\- State a medical or scientific reason if participants who are cancer survivors or those who are HIV positive will be excluded from the study. The full text of the Policies, Guidelines, and Procedures pertinent to this requirement is available at http://ctep.cancer.gov/protocolDevelopment/templates\_applications.htm.

Individuals with a history of a different malignancy are ineligible except for the following circumstances. Individuals with a history of other malignancies are eligible if they have been disease-free for at least 5 years and are deemed by the investigator to be at low risk for recurrence of that malignancy.

HIV-positive individuals on combination antiretroviral therapy are ineligible because of the potential for pharmacokinetic interactions with ferumoxytol and the propensity to have inflammatory adenopathy.

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